Facebook announced that it will begin testing a new Facebook Messaging system

If you thought that seeing advertisements in your Facebook news feed was annoying, get ready for Facebook's latest marketing scheme: ads sent to your inbox.

Facebook announced that it will begin testing a new Facebook Messaging system, where users can no longer choose to have just friends or connections message their inbox; instead, people (or marketers) can pay to have messages sent to you.

Right now, relevant messages from friends can be sent to your inbox while other less relevant messages are sent to the "Other" folder. What non-friends or marketers can do is pay to make sure their message is sent to your inbox instead of the "Other" folder.

"Today we’re starting a small experiment to test the usefulness of economic signals to determine relevance," said Facebook's announcement. "This test will give a small number of people the option to pay to have a message routed to the Inbox rather than the Other folder of a recipient that they are not connected with.

"Several commentators and researchers have noted that imposing a financial cost on the sender may be the most effective way to discourage unwanted messages and facilitate delivery of messages that are relevant and useful."

Facebook said the new service will have restrictions, such as keeping it to personal messages only and allowing only one per week during the testing phase. Facebook said it will allow people to message someone they may have seen speak live or perform, but aren't friends with, or seek others out for job opportunities (sort of like LinkedIn, where you have to upgrade to a paid account to send someone private InMail).

However, it's likely that Facebook is just doing this to allow marketers greater reach to its one billion monthly active users.

Just last month, Google's Vice President of Product Bradley Horowitzbashed Facebook's approach to ads. He criticized the fact that ads are forced into people's news feeds. He even went as far as comparing Facebook ads to a guy with a sandwich board popping in between a father and his daughter during an important conversation.

"We don't have to make next week's payroll by jamming ads at users," said Horowitz.